This research involves an investigation into the toxicity of chemically reactive epoxide metabolites, as exemplified by the case of bromobenzene and its biotransformation products. Current work involves the synthesis of various areneoxide derivatives of bromobenzene and substituted bromobenzenes and detailed study of the physicochemical properties and reactivity of these compounds. In addition mechanistic studies of the enzyme epoxide hydrase are under way. A newly devised photometric assay is being used to evaluate inhibitors of the enzyme as well as to investigate its mechanism through kinetic isotope effect studies.